Coupled behavior of rock joints

The behavior of rock joints under various coupled processes is reviewed under four broad categories: hydromechanical processes, thermohydromechanical processes, hydromechanical-chemical processes, and thermomechanical-hydrochemical processes. The state-of-the-art and possible directions of further research in these coupled processes are discussed. Rock joint behaviors considered include not only dilation, closure, shear and joint propagation, but also changes in flow permeability and chemical sorption and retardation capabilities. These properties are of critical concern in practical considerations of the rock mass as a medium to store and isolate chemical and radioactive wastes. Investigations of coupled processes in two-fracture systems and multi-fracture systems are pointed out as interesting areas for future research. The need to consider coupled processes in borehole testing procedures involving rock joints is emphasized. 70 refs., 12 figs.